java NIO server and client communicate with each other

Directory overview:

server code

NettyServer：

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioDatagramChannel;


public class NettyServer {

    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioDatagramChannel.class)
                    .option(ChannelOption.SO_BROADCAST, true)    //广播
                    .option(ChannelOption.SO_RCVBUF, 2048 * 1024)// 设置UDP读缓冲区为2M
                    .option(ChannelOption.SO_SNDBUF, 1024 * 1024)// 设置UDP写缓冲区为1M
                    .handler(new MyChannelInitializer());

            ChannelFuture f = b.bind(7398).sync();
            System.out.println("服务端已启动......");
            f.channel().closeFuture().sync();
        } finally {
            //优雅的关闭释放内存
            group.shutdownGracefully();
        }

    }
}

MyServerHandler：

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.DatagramPacket;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;

public class MyServerHandler extends SimpleChannelInboundHandler<DatagramPacket> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
        String msg = packet.content().toString(Charset.forName("UTF-8"));
        System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + " UDP服务端接收到消息：" + msg);
        //向客户端发送消息
        Scanner str = new Scanner(System.in);
        new Thread(() -> {
            while(true){
                System.out.println("你想对客户端说：");
                String line = str.nextLine();
                // 由于数据报的数据是以字符数组传的形式存储的，所以传转数据
                byte[] bytes = line.getBytes(Charset.forName("UTF-8"));
                DatagramPacket data = new DatagramPacket(Unpooled.copiedBuffer(bytes), packet.sender());
                ctx.writeAndFlush(data);//向客户端发送消息
            }
        }).start();
    }

MyChannelInitializer：

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioDatagramChannel;

public class MyChannelInitializer extends ChannelInitializer<NioDatagramChannel> {

    private EventLoopGroup group = new NioEventLoopGroup();

    @Override
    protected void initChannel(NioDatagramChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        // 解码转String，注意调整自己的编码格式GBK、UTF-8
        //pipeline.addLast("stringDecoder", new StringDecoder(Charset.forName("GBK")));
        pipeline.addLast(group, new MyServerHandler());
    }

}

client code

NettyClient：

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.Channel;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.DatagramPacket;
import io.netty.channel.socket.nio.NioDatagramChannel;
import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import java.util.Scanner;

public class NettyClient {

    public static void main(String[] args) {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group).channel(NioDatagramChannel.class)
                    .handler(new MyChannelInitializer());
            Channel ch = b.bind(7399).sync().channel();
            System.out.println("客户端已经连接服务器："+ch.isOpen());
            Scanner str = new Scanner(System.in);
            while(true){
                System.out.println("你想对服务端说：");
                String line = str.nextLine();
                //向目标端口发送信息
                ch.writeAndFlush(new DatagramPacket(
                        Unpooled.copiedBuffer(line, Charset.forName("UTF-8")),
                        new InetSocketAddress("127.0.0.1", 7398))).sync();
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {

            group.shutdownGracefully();
        }
    }

MyClientHandler：

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.DatagramPacket;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.Date;

public class MyClientHandler extends SimpleChannelInboundHandler<DatagramPacket> {

    //接受服务端发送的内容
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket packet) throws Exception {
        String msg = packet.content().toString(Charset.forName("UTF-8"));
        System.out.println(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + " UDP客户端接收到消息：" + msg);
    }

MyChannelInitializer：

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.nio.NioDatagramChannel;

public class MyChannelInitializer extends ChannelInitializer<NioDatagramChannel> {

    @Override
    protected void initChannel(NioDatagramChannel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        // 解码转String，注意调整自己的编码格式GBK、UTF-8
        //pipeline.addLast("stringDecoder", new StringDecoder(Charset.forName("GBK")));
        pipeline.addLast(new MyClientHandler());
    }

Startup process: first start the main method of the NettyServer class, and then start the main method of the NettyClient class

Call the renderings:

 Mutual communication complete